Island



(No Model.)

W. H. SAWYER.

ELECTRIC GAB-LE.

No. 269,470. Patented Dec. 19, 1882.

QZZtoz-aey.

UNITED STATES PATENT OFFICE.

ELECTRIC CABLE.

SPECIFICATION forming part of Letters Patent No. 269,470, dated December 19, 1882, Application filed September 27, 1882. (No model.)

To all erhom it may concern:

Be it known that l, WILLIAM H. SAWYER, a citizen of the United States, residing at Providence, in the county of Providence and of this specification.

My invention relates to electric cables of that class in which the several conducting insulated wires have an outer covering or sheath of metal for the purpose of preventing induction between the wires.

The object of my invention is toproduce a cable of this class in which the metallic coveringS of the wires shall be formed of thin sheet metal or metal foil so folded and secured that when the cable is completed no joint between the edges of the said metal coverings or sheaths will be exposed; audit has the further object to dispense with the hitherto-used expedients of soldering, brazing, spiral binding-wires, or other extra devices for securingthe lapping edges of the metallic strips which are folded around the respective cable-wires.

of insulated wires each of which is provided with a longitudinal wrapper or sheath formed of a strip of pliable sheet metal folded around the wire and having its edges lapped along one side thereof, said wires being twisted together, with the lap-joints of their metallic coverings on their inner surfaces and concealed from view. In such a cable there is nonecessity for soldering or other extra means offastenin'g. together the edges of the metallic strips surrounding the wires, respectively, as the twisting together of the wires with the joints inward causes the impingement of the said wires upon the sheath-joints of each other, so that the lapping edges of the sheaths will he held firmly together and in proper position to be concealed from view, and guarded against separation by the bending of the cable or its contact with exterior objects. Instead ofcove'ring all the wires with separate metallic sheaths before twisting them together, I may leave one of said wires without a metallic sheath, and give it a central position with respect to the others, which others I twist or coil around it so that the sheathings of all the other wires come in contact with the central wire, and thus give it a complete metallic covering, which has the efi'ect of preventinginduction between the central and other wires of the cable.

In the drawings, Figure lis a view of a per tion of a cable constructed according to my invention. Fig. 2 is a cross-section of the same. Fig. 3 illustrates a modified construction of the cable; and Fig. 4 is a cross-section of the modified cable.

Referring to Figs. 1 and 2, the metal-covered insulated wires of the cable are indicated by the letters A A A, and b b 1) indicate the insulating material of the wires.

0 c c designate themetallicsheathings, composed of thin strips of sheet metal, preferably tin-foil, one of which is folded around each wire outside ofits insu lating-covering,and the edges of this strip meet in a joint along one side of the wire. When the wires are twisted together the joints of the respective'strips are turned inwardly, or toward the center of the cable, which is composed oftwisted wires. The wires lying snugly adjacent to each other so confine thejoints of their respective sheathings that My improved cable consists of an assemblage no other fastening is necessary to hold the edges of the sheathing-strips together.-

Although I have shown a cable of only three wires, it will be obvious that the number of wires may be increased as desired.

Referring to Figs. 3 and 4, illustrating a modified construction of the cable, the letter D designates a central wire which is not provided with a separate metallic sheath, but is so surrounded by the sheathed wires A that induction between it and said wires is prevented. In this form of the cable, as well as in that shown in Figs. 1 and 2, thejoints of the sheathing-strips of the sheathed wires are turned inwardly, so that the twisting of the wires will brace said joints against rupture by the bending of the cable, and they willalso be shielded from disarrangement by the contact of the cable with outside objects. In the modified form of cable the sheathingjoints ofthe outer wires lie snugly against the central wire and spirally around it, and as many wires may be used as desired.

What I claim is- 1. An electric cable consisting of an asseinblag'e of insulated wires each of which is provided with a longitudinal wrapper or sheath formed of pliable sheet metal folded around the wire and havingl its edges meeting; on one side thereof, said wires being twisted together with the joints of their metallic sheathingstrips on their inner surfaces and concealed from View, substantially as described.

2. An electric cable composed of an assemblage of insulated wires each provided with a longitudinal sheathing-strip ot' pliable sheet metal folded around the wire and having its 1 edges meeting on one side thereof. said sheathed wires being twisted or coiled around an unsheathed central wire with their sheathing joints turned inwardly and impinging against said central wire, substantially as described.

In testimony whereof I afliX my signature in presence of two witnesses.

WILLIAM Iil. SAWYEl-t.

\Vitnesses:

JOHN 0. Poems, F. ll. ANGELL. 

